Means for mounting diaphragms



April 20 y 1926. I K l,58l,202

' A w. HAHNEMANN r Ay.

HEANS FOR MOUNTING DIAPHRAGMS Filed August 25 1921 A To all whom it may concer ni -a uniform tension.

Patented Api'. 20, '1926.

UNITED 'STATES I 1,581,2o2 PATENT OFFICE.

WALTEB EAH NEMANN, OF IKITZEBERG, NEAR KIL, AND WILHELM RUDOLPH, 035' KIEL, GERMANY, ASSIGNOBS '330 THE FIRM: SIGNAL GESELLSCHAFT M. B. H., OF

KIEL, 'WEBK BAVENSBEBG, GERMANY.

MEANS Fon MoUNrIhe DIAPHRAGMS.

' Application filed August 25, 1921. Serial No. 495,231. I

Be it known 'that' we, WVALTER HAHN MANN and lVILHELM: RUDOLPH; citizens of the German Republic, and residing at Kitzeberg, near Kiel, and at Kiel, County of Schleswig-Holstein, State of Prussia, Geri many, have invented certain new and useful Improvements in Means for Mounting Diaphragms, of which' the following is a specification. i

The invention relates to sound apparatus ot' the kind provided with a diaphragm for tran-smitting or collecting sound waves.

In sound apparatus of this type difficulty is experienced in 'mounting the diaphragm 1nthe casing surrounding the actual apparatus so-that on the one hand it completely closes the casing tightly, a requirement which is 'particularly important with submarine' sound apparatus, and on the other hand so that it does not bend and that it maintans i Hitherto for this purpose two methods have chiefly been employed, viz, either sol- 'dering the diaphragm in the edge of the casing or securing it by means of screws.

The soldering method has the reat disadvantage that the tension of the daphragm is altered during soldering 'so that it is impossible with different apparatus to make the tension' and thus also the tuning of the diaphragm quite equal. Furthermore, the diaphragm als gradually becomes loose in the soldered joint when strong pressures are exerted upon it so that its tension does not remain constant. The same drawback occurs also with diaphragms Secured by screws. In addition,. in this latter case, it is onl possible with dificulty to sea] the diap ragm uniforml tight because between every two screws' t ere are always relatively loose places.

The 'object of the invention is to remove these drawbacks. It consists in the feature that the diaphragm isembraced by means i of a shrunk ring or a structure actin'g in the manner of a shrunk ring and sealed tight. Sometimes it occurs that the pressure of the shrunk ring becomes too great and the casing itself as a whole is narrowed or compres'sed by this pressure. In consequence of that the diaphragm isbent and its tuning changed. According to the invention the outer pa r ofthe csing adjaccnt the ring s shaped n coni'cal form or tapered so that the ring s allowed to slide during contracting to a narrower place .of the casing. `An- .other method of preventing the casing from being narro wed consists in 'thickening the casing at the zone where the pressure of the ring acts.

Figs, 1 to 4: show examples of the inventon, all figures being sections through sound receiving apparatus with diaphragms mounted in accordance with theinvention or through parts of apparatus of this kind.

In Fig. 1 a is a casing enclosing the detcctor. forms a shoulder thereon. The diaphra'gm c has a marginal portion 'bent over at right angles to form `a fiange, and is mounted on The upper edge b of the casing a e the edge b of the case a where it is firmly 'pressed against the edge b by a ring d the conformation of which corresponds to the conformation of the edge b. Between the ring d and the edge of the casing a slot e remains free so that the ring d only rests on thediaphragm c. The ring al is provided at f with arecess in order to prevent the diaphragm c from being strained. The diaphragm c carries at its centre themcrophone g located in the interior of the case a. h is a tension ring adapted to be screwed against the 'diaphragm in order to regulate the tuning of .the latter.

as follows: The diaphragm c ispressed from annealed sheet in the prescribed form and i placed over the edge of the case. The ring d is then heated, placed over the diaphragm and pressed thereon from above by means of a wei ht. On cooling, the ring contracts and radially presses the diaphragm firmly on the edge b of the casing. When the weight is removed the cooled ring remains in the position to which it has been pressed by the weight. In this manner it is assured that the diaphragm is firmly pressed-not only radially but also from the top on the edge of the casing so that there is formed by the ring a uniform edge engagement from which the diaphragm oscillates.

In Fig. 2 a modified constructional form of the invention is represented. The reference characters correspond to those of Fig.

30 with the casing of the apparatus, of a ring,

ring d.

itself acts as shrunk ring. The casing a is heatd and embraces the diaphragm c so thaton cooling the casng the diaphragn is firmly pressed between the latter and the 'In Fig. 3 another modification of the in- -Vention is shown in which the outer part of the casing adjacent the shrunk ring has a conical form or tapers inwardly, the upper portion of this part being wider' than the lower portion. In contracting the ring slides or is caused to slide by ?forcing it toward the narrower portion. v

'In Fig; 4 the part of the casing adjacent the shrunk ring is much thicker than the other parts of the wall of the casing. The other reference characters in Figs. 3 and et are the same as in Figs. 1 and 2.

In the examples of F igs. 3 and 4; still another charactetistic feature of the invention is represented consisting of an annular border arising from the top face of the casing. This border serves to stretch the diaphragm. I In order i in given cases to avoid any straining of the diaphragn on the shrinking of the ring, it is preferably mounted hot after it is adjusted in its width so that in the hot condition it fits exactly.

We claim 1. In a sound apparatus, the eombination `ring being adapted to sea] the joint between and a dizphragm having a narginal portion interposed between the ring and casing and held tight by a clamping eflect exerted by the shrinkage ot one of the said parts between which it is interposed, the part of the wall of the casing adjacent the shrunk ring beingconsiderably thicker than 'the other parts of the wall.

4. In a sound appzratus, the combination with the casing of the apparatus, of a ring, and a diaphragm having a marginal portion interposed between the ring and casng and held tight by a clamping 'efiect exerted by the shrinkage of one of the said parte between which it is interposed and an annular border on the top face of the casing engaging the diaphragm.

5. The method of nounting and fzstening an oscillatory diaphragm on the casing of a -sound apparatus, consisting in bending a narginai portion of the diaphragm to form a flange, fitting the flange over the edge of the casing, fitting a ring over said fiange, and shrinking the ring in place so as to press the fiange tightly against the casing. 6. The method of mounting and scaling an oscillatory diaphragm on the casing of a sound apparatus, consisting in bending a marginal portion of the diaphragm to form a flange, fitting it over' the edge of the casng, heating a ring and tting itover said fiange, and shrinking the ring in place so as to press the flange tightly against the casing.

In testimony whereof we aflix our signatures.

WALTER HAHNEMANN. WILHELM RUDOLPH. 

